Why should you care?

Banks prefer procedures for money movement so rules stay in OracleCore, not copied in five microservices.

See it live — copy this example

Run these statements in SQL Developer or SQL*Plus against your lab PDB. Prefer a practice user — not SYS — for application SQL.

CREATE OR REPLACE PROCEDURE credit_account (
  p_customer_id IN NUMBER,
  p_amount      IN NUMBER
) AS
BEGIN
  IF p_amount <= 0 THEN
    RAISE_APPLICATION_ERROR(-20001, 'Amount must be positive');
  END IF;

  UPDATE customers
  SET balance = balance + p_amount
  WHERE customer_id = p_customer_id;

  IF SQL%ROWCOUNT = 0 THEN
    RAISE_APPLICATION_ERROR(-20002, 'Customer not found');
  END IF;

  COMMIT;
END;
/

-- Call it
BEGIN
  credit_account(1, 500);
END;
/

What happened?

• Parameters are IN values.
• RAISE_APPLICATION_ERROR stops bad input.
• UPDATE changes balance.
• SQL%ROWCOUNT checks if a row was updated.

Practice next

1. Create the customers table if needed.
2. Compile the procedure (F5 in SQL Developer).
3. Call credit_account and SELECT the balance.
4. Add a debit_account procedure.
5. Log the operation into an audit table.

Remember

Procedures encapsulate business steps. Validate inputs before UPDATE. Test both success and error paths.

Teller credit

Branch deposits must update balance with the same rules every time.

Outcome: One procedure call from the app; consistent validation.